Key information relevant to the recruitment process for the
overall study, such as dates of the recruitment period and locations

No text entered.

Pre-Assignment Details

Significant events and approaches for the overall study
following participant enrollment, but prior to group assignment

One randomized participant withdrew consent prior to vaccine administration and was not included in the participant flow data or in any analysis population.

Reporting Groups

Description

CSL425 (15 Mcg) Cohort A

Participants aged 6 months to less than 3 years received two doses of CSL425 (15 mcg of haemagglutinin antigen per 0.25 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

CSL425 (30 Mcg) Cohort A

Participants aged 6 months to less than 3 years received two doses of CSL425 (30 mcg of haemagglutinin antigen per 0.5 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

CSL425 (15 Mcg) Cohort B

Participants aged 3 years to less than 9 years received two doses of CSL425 (15 mcg of haemagglutinin antigen per 0.25 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

CSL425 (30 Mcg) Cohort B

Participants aged 3 years to less than 9 years received two doses of CSL425 (30 mcg of haemagglutinin antigen per 0.5 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

Explanation of how the number of participants for analysis was determined.
Includes whether analysis was per protocol, intention to treat, or another method.
Also provides relevant details such as imputation technique, as appropriate.

No text entered.

Reporting Groups

Description

CSL425 (15 Mcg) Cohort A

Participants aged 6 months to less than 3 years received two doses of CSL425 (15 mcg of haemagglutinin antigen per 0.25 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

CSL425 (30 Mcg) Cohort A

Participants aged 6 months to less than 3 years received two doses of CSL425 (30 mcg of haemagglutinin antigen per 0.5 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

CSL425 (15 Mcg) Cohort B

Participants aged 3 years to less than 9 years received two doses of CSL425 (15 mcg of haemagglutinin antigen per 0.25 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

CSL425 (30 Mcg) Cohort B

Participants aged 3 years to less than 9 years received two doses of CSL425 (30 mcg of haemagglutinin antigen per 0.5 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

During the 7 days after the second vaccination and up to Day 20 after the second vaccination if AE was ongoing at Day 7.

Safety Issue

Yes

Population Description

Explanation of how the number of participants for analysis was determined.
Includes whether analysis was per protocol, intention to treat, or another method.
Also provides relevant details such as imputation technique, as appropriate.

The Safety Population comprised all participants who received at least one dose of the vaccine and provided follow-up safety data.

Reporting Groups

Description

CSL425 (15 Mcg) Cohort A

Participants aged 6 months to less than 3 years received two doses of CSL425 (15 mcg of haemagglutinin antigen per 0.25 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

CSL425 (30 Mcg) Cohort A

Participants aged 6 months to less than 3 years received two doses of CSL425 (30 mcg of haemagglutinin antigen per 0.5 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

CSL425 (15 Mcg) Cohort B

Participants aged 3 years to less than 9 years received two doses of CSL425 (15 mcg of haemagglutinin antigen per 0.25 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

CSL425 (30 Mcg) Cohort B

Participants aged 3 years to less than 9 years received two doses of CSL425 (30 mcg of haemagglutinin antigen per 0.5 mL dose) by intramuscular injection into the deltoid region of the arm on Day 0 and Day 21.

Measured Values

CSL425 (15 Mcg) Cohort A

CSL425 (30 Mcg) Cohort A

CSL425 (15 Mcg) Cohort B

CSL425 (30 Mcg) Cohort B

Number of Participants Analyzed
[units: participants]

77

71

100

99

Duration of Solicited AEs After the Second Vaccination
[units: days]Mean ± Standard Deviation

Pain at injection site

1.67
± 0.966

1.64
± 1.002

1.90
± 1.179

1.80
± 1.040

Redness at injection site

1.69
± 1.004

2.14
± 1.037

1.92
± 1.055

1.70
± 0.822

Swelling/induration at injection site

1.74
± 0.872

2.32
± 1.108

2.24
± 1.348

2.27
± 1.751

Nausea/vomiting

5.00
± 8.832

1.00
± 0.000

1.43
± 0.787

1.11
± 0.333

Diarrhoea

3.40
± 3.777

1.25
± 0.452

1.40
± 0.894

2.00
± 1.000

Loss of appetite

3.15
± 4.475

1.73
± 0.883

NA
± NA
[1]

NA
± NA
[1]

Irritability

2.57
± 2.410

2.10
± 1.533

NA
± NA
[1]

NA
± NA
[1]

Fever

2.14
± 3.005

1.63
± 1.165

1.54
± 0.877

1.67
± 1.414

Headache

NA
± NA
[2]

NA
± NA
[2]

1.33
± 0.686

1.73
± 2.412

Muscle ache

NA
± NA
[2]

NA
± NA
[2]

1.60
± 0.516

1.29
± 0.756

Malaise

NA
± NA
[2]

NA
± NA
[2]

1.20
± 0.422

2.00
± 1.826

[1]

Not solicited for in Cohort B

[2]

Not solicited for in Cohort A

No statistical analysis provided for Duration of Solicited AEs After the Second Vaccination

10. Secondary:

Incidence of Serious Adverse Events (SAEs), Adverse Events of Special Interest (AESIs), and New Onset of Chronic Illnesses (NOCIs) [ Time Frame: Up to 180 days after the last vaccination ]

Frequency and Intensity of Unsolicited Adverse Events After the First or Second Vaccination [ Time Frame: During the 21 days after each vaccination; up to 180 days after the last vaccination for SAEs, AESIs, and NOCIs ]